Green Line E branch

Massachusetts Bay Transportation Authority

Company type	Public agency
Industry	Public transport
Predecessor	Metropolitan Transit Authority, Boston Elevated Railway
Founded	1964
Headquarters	Boston , United States
Area served	Boston, Cambridge, Medford, Somerville, Massachusetts
Owner	Commonwealth of Massachusetts
Website	mbta.com

The E branch—also referred to as the Huntington Avenue branch and formerly known as the Arborway Line—is a light rail route managed by the Massachusetts Bay Transportation Authority (MBTA) as part of the Green Line network. It serves the cities of Boston, Cambridge, Medford, and Somerville in Massachusetts. The line operates in mixed traffic along South Huntington Avenue and Huntington Avenue between and , containing the MBTA's final remaining street-running tracks used for revenue service. Between Brigham Circle and , trains travel within the median strip of Huntington Avenue before entering the Huntington Avenue subway. West of , the line joins the Boylston Street subway, continues through via the Tremont Street subway, then crosses the Lechmere Viaduct to , following the Medford Branch onward to . As of February 2023, weekday peak periods see trains every eight minutes, with frequencies ranging from eight to nine minutes at other times, deploying between 13 and 17 trains (equivalent to 26 to 34 light rail vehicles).

Horse-drawn streetcar service commenced in 1857 along Centre and South streets in Jamaica Plain, extending to Tremont Street (now part of Huntington Avenue) by 1859, and reaching the eastern section of Huntington Avenue between 1881 and 1884. Electrification was introduced in Jamaica Plain in 1891 and expanded to Huntington Avenue in 1894. Multiple branches west of Brookline Village opened from 1894 through 1900; both Jamaica Plain and Huntington Avenue lines began utilizing the Tremont Street subway starting in 1897. A connecting track on South Huntington Avenue was established in 1903, enabling Jamaica Plain cars to operate via Huntington Avenue. During the 1920s, Jamaica Plain service extended to , while western branches were reorganized and subsequently reduced during the 1930s.

The Huntington Avenue subway debuted in 1941, significantly cutting travel times through the heavily congested Copley Square area. Ownership shifted from the Boston Elevated Railway to the Metropolitan Transit Authority in 1947, then later transferred to the MBTA in 1964. The Tremont Street subway was designated as the Green Line in 1965, with the Huntington Avenue route assigned as the E branch two years later. Early MBTA operations saw numerous service changes, including a substantial overhaul between 1980 and 1982. In 1985, service beyond Brigham Circle was replaced by route 39 bus service—a change initially intended as temporary but ultimately made permanent despite public opposition—although service to Heath Street resumed in 1989 following street track renovations on Huntington Avenue. Throughout this period, downtown terminal locations shifted multiple times; from 1987 until 2020, Lechmere served predominantly as the terminus. In May 2020, operations were truncated to North Station due to Green Line Extension construction, temporarily extending to in March 2022 before being permanently extended to Medford/Tufts by December 2022.

Horsecar lines

The origins of the E branch trace back to several horsecar routes, beginning with the West Roxbury Railroad—a horsecar line inaugurated on November 14, 1857, serving West Roxbury. This line ran from to Jamaica Plain via Lowell Street (present-day Columbus Avenue), Centre Street, and South Street. The Metropolitan Railroad leased this line, enabling through service between Jamaica Plain and downtown Boston via Tremont Street. The journey along this route took over an hour with a fare of ten cents. A two-track carhouse equipped with a waiting room was situated at Jamaica Street in Jamaica Plain; meanwhile, Metropolitan Railroad’s primary carhouse was located at Roxbury Crossing. In 1858, a connection linking Lowell Street to John Eliot Square was constructed, allowing Jamaica Plain cars access to the Washington Street line (via ) for travel into downtown Boston. That same year marked upgrades on the Jamaica Plain line to accommodate heavier ridership demands, including partial double-tracking.

On August 1, 1859, permission was granted for a branch extending northwest from Brookline Village along Washington Street (later renamed Tremont Street east of Brookline Village and Huntington Avenue between Brigham Circle and Brookline Village). This branch opened on October 26, 1859, with authorization for double-tracking granted by 1879. Service west of Brookline Village operated intermittently.

As Back Bay developed into an important district, Huntington Avenue emerged as a vital transit corridor. On March 18, 1881, the Metropolitan Railroad secured rights to construct a double-track line on Huntington Avenue stretching from Copley Square to West Chester Park (later known as Massachusetts Avenue). By September of that year, a segment opened servicing exhibitions at Mechanics Hall and the New England Fair Building. An extension from West Chester Park to Brigham Circle was completed by October 1, 1884, establishing a second route connecting Brookline and Boston. Around late 1884, a branch running along Longwood Avenue reaching began operation. Circa 1888, another branch extended westward from Brookline Village along Boylston and Cypress Streets serving Pill Hill—likely competing with Newton Circuit services provided by the Boston and Albany Railroad since its inception in 1886.

Electrification

In November 1887, the Metropolitan company merged with the West End Street Railway, unifying Boston's streetcar systems under a single operator. After successfully electrifying the Beacon Street line between 1888 and 1889, West End quickly transitioned its entire network to electric power. The route from Jamaica Plain to the Northern Depots switched to electric traction on October 14, 1891, followed shortly by other lines on Tremont Street on October 22. In early 1901, the horsecar barn in Jamaica Plain was replaced by a modern electric carhouse capable of housing 150 streetcars and providing passenger amenities.

Electrification of the Huntington Avenue route occurred during 1893–94, with work concluding by July 1894 except for a section near the Riverway. On August 4, full electric service began on Brookline routes along Huntington Avenue, including Washington Street (extended to Park Street), Cypress Street, and Tremont Street tracks reaching Roxbury Crossing. The Washington Street branch was extended to Beacon Street at on September 1, enabling continuous service from Reservoir through Brookline Village. On August 15, 1896, the Beacon Street line was lengthened along Chestnut Hill and Commonwealth Avenues to Lake Street, connecting with the Commonwealth Avenue Street Railway.

In November 1894, the Cypress Street branch was extended slightly to accommodate a new carhouse with space for 36 streetcars; this facility expanded in 1897 to hold approximately 79 vehicles. The Longwood Avenue branch was electrified by 1895 but only within Boston city limits due to infrastructure constraints and Brookline's directive to remove tracks west of its boundary. Between 1894 and 1896, Huntington Avenue was transformed into a boulevard with streetcar tracks relocated to a dedicated median east of Brigham Circle.

The initial segment of the Tremont Street subway opened on September 1, 1897. Lines entering the subway via the Public Garden incline included routes from Cypress Street via Huntington Avenue and cross-town Jamaica Plain services. The southern portion of the subway extending to the Pleasant Street incline opened on September 30, routing Jamaica Plain cars through Tremont Street into the subway; Reservoir service via Huntington Avenue commenced on November 8. Shortly thereafter, Longwood Avenue and Lake Street cars also utilized the subway. Additional early services operating east of Massachusetts Avenue along Huntington Avenue included a Forest Hills–Park Street route via Washington Street starting November 1, 1898, as well as a Humboldt Avenue–East Boston Ferries route.

Expansion

Two connecting lines began operation in August 1900. New tracks installed on Harvard Street between Brookline Village and allowed through service from Allston directly to the subway via Huntington Avenue. The Ipswich Street line introduced a route linking Brookline Village and the subway; initially service terminated at Cypress Street. On September 29, 1900, Ipswich Street service extended westward along Boylston Street from Cypress Street to Chestnut Hill Avenue, then further reached the Newton line at Chestnut Hill by November 19. Through service on Longwood Avenue ceased August 8, 1901, replaced by a shuttle between Brookline Avenue and Huntington Avenue. On May 5, 1903, the Boston and Worcester Street Railway (B&W) commenced operations terminating initially at Chestnut Hill but expanded over BERy tracks along Boylston Street and Huntington Avenue to Park Square on July 6.

The Main Line Elevated began service between and on June 10, 1901. Utilizing outer tracks of the Tremont Street subway (the Pleasant Street incline tracks), it provided a faster downtown connection than surface streetcars, prompting adjustments within the network. Jamaica Plain routes were redirected to Dudley Square transfer station; shortly after, a new Dudley–Brookline line was launched. Tracks along South Street between Jamaica Plain and Forest Hills Square received approval in June 1900; construction started April 1902 with the connector opening May 17. On May 11, 1903, Boston Elevated Railway inaugurated tracks on South Huntington Avenue between Centre Street and Huntington Avenue, enabling Jamaica Plain–Park Street service via South, Centre, South Huntington, and Huntington streets.

By March 1907, regular services west of Massachusetts Avenue on Huntington Avenue included routes from Jamaica Plain via South Huntington Avenue; Lake Street via Washington Street; via Harvard Street; and Allston Carhouse via Harvard Street—all entering the subway and looping at Park Street—alongside Cypress Street–Dudley cars and B&W lines. Additional routes operated along South and Center Streets in Jamaica Plain such as Forest Hills–Park Street (via Columbus Avenue), Jamaica Plain Carhouse–Dudley, and Jamaica Plain–. Some Allston–Park Street cars were rerouted over Longwood Avenue starting October 12, 1907, replacing a shuttle service. On November 30, 1908, Main Line trains switched into the Washington Street Tunnel; outer Tremont subway tracks reopened for streetcars December 4 with certain lines extended or rerouted from Dudley. Cars entering the subway on Boylston Street looped at Park Street; those entering at Pleasant Street (including lines from Brookline via Tremont and Jamaica Plain via Roxbury Crossing) exited at Canal Street and looped at .

The Washington Street Elevated extended service to on November 22, 1909, reinforcing its function as a transfer hub. Requests to extend South Huntington Avenue line from Jamaica Plain Carhouse to Forest Hills began prior to completion and persisted through the following decade. Free transfers at Jamaica Plain Carhouse commenced March 1, 1913. In April that year BERy indicated willingness to introduce express runs along South Huntington Avenue but faced equipment shortages preventing extension. On June 12, 1915, the Hyde Park–Forest Hills line was extended to Jamaica Plain Carhouse; concurrently Forest Hills–North Station (via Columbus Avenue) was truncated to Jamaica Plain Carhouse to allow increased frequency on Forest Hills service. This adjustment proved unpopular; by October 2, Hyde Park line reverted to Forest Hills while the Charles River line was extended instead providing a direct West Roxbury connection onto South Huntington Avenue line. On March 1, 1924 BERy opened an internal streetcar transfer station within Arborway Yard easing congestion at Forest Hills station. Shortly after this improvement South Huntington Avenue line was extended to Arborway enhancing connectivity with other routes.

Reroutes and bus conversions

Beginning January 25, 1913, the Allston–Brookline Village–Park Street routes were extended to reach North Station, allowing continuous service between Back Bay and North Station. On May 24, 1914, the BERy inaugurated the Allston–Dudley crosstown line passing through Brookline Village. The Boylston Street subway commenced operations on October 3, 1914, extending westward to Kenmore Square and replacing the Public Garden Incline portal. Between 1914 and 1915, outer terminals for Washington Street services underwent several changes: the Oak Square–Park Street route was shortened to Allston–Park Street, and a new Cypress Street–Park Street line was introduced via Longwood Avenue. In November 1915, Washington Street service was extended back to Lake Street while Beacon Street service was reduced to Reservoir.

By 1921, Huntington Avenue hosted four subway services: Lake Street, Jamaica Plain, Longwood, and Opera Place short-turns. BERy proposed a semi-rapid transit system using two-car trains for Brookline Village–Park Street and shuttle services for Jamaica Plain and Lake Street routes. Local opposition led to plan modifications; starting February 6, 1922, two-car trains operated between Brookline Village and Park Street while Washington Street ran as a shuttle from Brookline Village to Lake Street. Francis Street–Park Street short-turns were operated sporadically from 1926 through 1934.

In June 1925, Ipswich Street service was truncated to Massachusetts–Chestnut Hill, ending direct Chestnut Hill-downtown connections; this was partially restored in March 1926 by exchanging terminals with Huntington Avenue lines. Evening peak express service on South Huntington Avenue cars began in December 1928. The Longwood Avenue shuttle transitioned to bus service on June 22, 1925, which ceased in 1942; transit returned along this corridor with route 55 in 1972. The Washington Street shuttle converted to bus operation on April 24, 1926; it was rerouted to Brighton Center in 1928 and ultimately became route 65. Tracks were removed during World War II.

The paving of Worcester Turnpike as Massachusetts Route 9 during the 1930s necessitated streetcar removals; buses replaced Boston and Worcester Street Railway cars on June 11, 1932. By November of that year, paving reached Chestnut Hill; as a result, Huntington Avenue cars were cut back to Cypress Street while Ipswich Street cars terminated at Brookline Village, accompanied by a new Chestnut Hill–Brookline Village bus route. In mid-1933, Ipswich Street operated as a short shuttle with an added Brookline Village–Kenmore bus route. The Cypress Street Carhouse closed on December 3, 1933, consolidating routes at Arborway Yard.

On June 10, 1934, Cypress Street service was reduced to Brookline Village with buses covering Cypress Street–Kenmore segments; these routes merged in 1985 to form MBTA bus route 60. The Allston–Dudley line switched to buses on September 10, 1938; simultaneously, Huntington Avenue’s Brookline Village cars were shortened with additional Brigham Circle short-turns. To improve traffic flow through Brookline Village square, the city demolished the transfer station immediately.

Huntington Avenue subway

As early as 1906, plans for a subway along Huntington Avenue aimed to relieve streetcar congestion on Boylston Street and Copley Square. At that time, streetcars operated mixed with traffic except for a dedicated median west of Dartmouth Street. A proposed subway extension reaching Mechanics Hall surfaced in 1911 but was rejected in 1912 due to expectations that new subways would reduce Boylston Street streetcar volumes.

In May 1924, the state legislature tasked the Metropolitan District Commission with planning an expanded rapid transit network that included extending the Boylston Street Subway beneath Governors Square. A December 1926 report recommended reorganizing existing streetcar tunnels into two rapid transit lines utilizing high-floor vehicles. One line would run from Lechmere through the Tremont Street subway paralleling New Haven Railroad tracks toward Providence before surfacing along Huntington Avenue to Francis Street (Brigham Circle). Proposed new stations included Pleasant Street, Back Bay, West Newton Street, and Massachusetts Avenue with consolidated stops at key points. Surface transfers between streetcars and rapid transit would be available at Brigham Circle. An extension toward Brookline Village was also contemplated.

Following closure of the Berkeley Street line around 1930, only Huntington Avenue cars continued using the Boylston Street Incline. In June 1932, legislation authorized construction of a tunnel from Gainsborough Street under Huntington Avenue and nearby streets leading to Park Street station; however, BERy rejected this plan citing duplication and cost concerns—legislation barred route alterations.

In 1933 Mayor James Michael Curley proposed an $8.5 million subway project from Copley Square to Longwood Avenue funded via the National Industrial Recovery Act rather than local borrowing. That year the legislature permitted greater routing flexibility. Multiple tunnel designs emerged considering extensions reaching as far west as Longwood Avenue or as short as Dartmouth Street with various branching near Copley Square.

By October 1936 construction approval was granted for a subway extending nearly to West Newton Street under a Works Progress Administration (WPA) project costing $1.715 million with approximately $539,000 funded by the city government. Both Boston City Council and Boston Elevated Railway approved plans in April 1937; construction commenced September 18 of that year. In 1938 the project expanded to Opera Place featuring underground stations at Symphony and Opera Place plus an automobile underpass beneath Massachusetts Avenue near Symphony station; federal approval arrived in August.

The subway comprises twin tunnels approximately long running side-by-side except at Symphony station where they flank an underpass. Total costs reached $7.13 million (equivalent today), with $1.93 million contributed by the city and $5.20 million federally funded—making it the second-largest WPA project after LaGuardia Airport.

The Huntington Avenue subway opened February 16, 1941 bringing most streetcar operations underground. At opening three routes utilized this line:

• 39: –
• : Jamaica Plain–
• 57: Francis Street (Brigham Circle)–Park Street (a short-turn variant of route 39)

A turning loop at Brigham Circle was constructed in 1945 for new PCC streetcars requiring loops; route 57 extended there December 15 that year with PCC service starting January 3, 1946. From June 1947 through June 1949 and again during the 1950s a Northeastern University–Park Street shuttle operated.

Route 41 converted entirely to bus operation on June 8, 1949. In 1954 route 57 extended service to its surface terminal at Brigham Circle; weekday operations ceased September 1, 1961 with its number reassigned later that year to a brief Boylston–Pleasant Street shuttle service. Between September 1962 and March 1965 a single Lechmere–Heath Street trip ran during morning peak hours fulfilling school demand—the only instance of three-car PCC trains operating on Huntington Avenue.

MBTA period

In 1964, the Massachusetts Bay Transportation Authority (MBTA) took over from the MTA and introduced color-coded subway lines in 1965, designating the Tremont Street subway as the Green Line. Starting December 26, 1964, short-turn trips to Heath Street began utilizing a new loop at Government Center to serve the Prudential Center; however, this was cut back to Park Street the following month and then reinstated to Government Center on March 25, 1967. Peak-time short turns to Heath Street saw a temporary increase in 1966 but ceased by November of that year. By January 1972, these short-turn trains were reduced from two-car sets to single cars.

In 1967, the Green Line branches were assigned letter designations, with Huntington Avenue identified as the E branch. The following year, efforts began to widen Huntington Avenue east of Brigham Circle, which involved closing three stops and expanding platforms at five others. Although federal budget reductions in 1969 delayed this project, work resumed in 1971 with track replacements between Brigham Circle and Parker Hill Street. The revived 1972 plan included adding a footbridge at Northeastern; however, opposition from the Museum of Fine Arts and the economic downturn from 1973 to 1975 further postponed progress.

Between September 1976 and January 1977, night subway service was replaced by buses to facilitate upgrades. Due to harsh winter conditions and a shortage of cars, service during peak and midday hours was truncated to Heath Street starting January 1, 1977, with route 39 buses covering the segment from Arborway to Copley until March. Throughout 1977, service modifications continued as buses substituted streetcars beyond Heath Street because of delays in introducing new Boeing LRV vehicles; full Arborway service was restored by December 31, 1978. New LRVs were first deployed on Northeastern short turns in January 1978 and extended to Heath Street by April.

Although the planned roadway widening was never finalized, the MBTA reconstructed the line for LRVs alongside other Huntington Avenue infrastructure improvements. This work largely adhered to initial plans except for omitting the Northeastern footbridge; three proposed stations plus Parker Street were eliminated, while remaining stops received wider platforms. On March 21, 1980, service was reduced to a Symphony–Park Street LRV shuttle with route 39 buses replacing other segments. The shuttle was extended to Northeastern in June and further to Brigham Circle by September. Due to budget constraints, Symphony station closed on January 3, 1981. Restoration of outer line service was delayed but resumed on June 26, 1982, including peak short turns to Heath Street and reopening Symphony station.

Heath Street service was extended to Lechmere on January 2, 1983. A snowstorm in February temporarily shut down the Arborway Line; during this period, a shuttle operated between Lechmere and Government Center replacing Heath Street cars until late March. Construction on the Southwest Corridor caused a cutback between October and November 1983 to , with buses covering routes beyond that point. Short-turns to Heath Street resumed using LRVs on September 18, 1984.

Controversy over Arborway restoration

On December 28, 1985, due to road construction along Huntington Avenue, the Arborway Line was indefinitely replaced by route 39 bus service running between Arborway and , marking the end of PCC streetcar operations on the Green Line (though they continued on the Mattapan Line). LRV service restarted up to Brigham Circle on July 26, 1986; weekday terminals were at Lechmere while nights and weekends terminated at Government Center. By June 20, 1987, all Brigham Circle trips extended to Lechmere using newer Type 7 LRVs. Service to Heath Street resumed on November 4, 1989; however, route 39 buses continued south of Heath Street. In December of that year, route 39 extended service to Back Bay station for Orange Line transfers with reduced fares offered. By 1990, route 39 had become MBTA’s busiest bus corridor with an average daily ridership of 19,040 passengers. Between 2000 and 2017, buses operated using a loop originally constructed for but never utilized by Green Line trains at .

The proposal to reinstate E branch service along Arborway generated debate: Jamaica Plain residents generally supported it while MBTA officials opposed restoring the lengthy street-running segment. A study conducted in 1987 estimated restoration costs at $37.4 million plus annual operating expenses of $5.9 million but predicted greater ridership compared to bus service. To resolve a lawsuit filed by the Conservation Law Foundation regarding increased vehicle emissions linked to the Central Artery/Tunnel Project, the Massachusetts Executive Office of Transportation and Construction (EOTC) agreed in a 2000 Administrative Consent Order (ACO) to restore streetcar operations beyond Heath Street toward Arborway. This commitment was incorporated into the State Implementation Plan for Clean Air Act compliance due to failure in meeting air quality standards. Following opposition from MBTA and community groups, a revised settlement replaced this requirement with alternative projects providing comparable regional air quality benefits but not directly benefiting the E branch corridor; EOTC pledged consideration of other transit improvements in Arborway.

A study in 2004 highlighted concerns that street-running tracks along South and Centre streets would worsen congestion and potentially obstruct emergency vehicles. In March 2005, Councilor John Tobin called for track removal; by that time both tracks and overhead wires had deteriorated beyond functionality. The Arborway Committee pursued legal action in 2007 but faced dismissal of their case by an appeals court in 2011 due to lateness—effectively ending restoration efforts. Approximately 140 remaining overhead wire support poles were removed by MBTA toward late 2023. Meanwhile, Boston city officials have proposed extending the E branch southward toward Hyde Square in Jamaica Plain.

During the Orange Line shutdown from August through September 2022, dedicated bus lanes were introduced along several Boston streets serving route 39; four segments were made permanent: Boylston Street (Ring Road to Clarendon), Clarendon (Boylston to Columbus Avenue), St. James Avenue (near Berkeley to Dartmouth), and Huntington Avenue (Brigham Circle to Gainsborough), servicing routes including routes 39 and . In September 2023, MBTA reported that these dedicated lanes on Huntington Avenue reduced travel times by up to two minutes during peak periods.

In May 2022, MBTA unveiled a draft plan for systemwide redesign proposing an extension of route 39 through via and , substituting portions of routes , , and , while discontinuing service between Longwood Avenue and Back Bay. However, revisions issued in November 2022 restored route 39’s existing routing while extending a higher-frequency route 47 instead toward Union Square.

Subsequent Developments

On October 20, 1996, the Muddy River flooded the central subway, causing a suspension of E branch operations which were temporarily substituted with bus service. Restoration of service occurred in stages: Northeastern station reopened on October 25, Brigham Circle followed on November 9, and Heath Street resumed service by December 7. Between July and December 2000, track maintenance on South Huntington Avenue required truncating the line at Brigham Circle, supplemented by express buses.

During the early 2000s, the MBTA enhanced several surface stops through the Light Rail Accessibility Program, introducing raised platforms. Temporary portable lifts were installed at Heath Street around 2000. Mid-2002 weekend bus replacements supported ongoing station construction. By 2003, accessible platforms had been completed at Northeastern, Museum of Fine Arts, Longwood, Brigham Circle, and Heath Street as part of a $32 million project that upgraded thirteen stations across the B, C, and E branches. Accessibility improvements at Prudential station coincided with development near 111 Huntington Avenue during 2002–03.

From June 2004 until November 2005, E branch trains terminated early at due to the replacement of the Causeway Street elevated with a new tunnel. Service was again curtailed to Brigham Circle for track work from September to December 2006. Starting in March 2011, three-car trains were briefly operated. Renovations at prompted a service reduction to North Station between April and November 2011.

Amid budget constraints, weekend service was reduced to Brigham Circle on July 1, 2012, eliciting community pushback. This reduction was quietly reversed on October 13, 2012; frequency was slightly decreased to preserve full-line weekend coverage without additional expense. This adjustment became official in the December timetable.

Between August 3 and 29, 2020, bus replacements operated between Prudential and Heath Street to expedite track work that included replacing seven grade crossings and nearly 3,000 feet of rail. A comparable month-long closure occurred from August 2 to 29, 2021 between Heath Street and Brigham Circle.

Accessibility upgrades at Symphony station commenced in 2023 but were halted in 2024 due to bids exceeding budget expectations.

On May 24, 2020, E branch service was cut back from Lechmere to North Station to facilitate demolition of the former Lechmere Elevated structure and connect the Lechmere Viaduct with the Green Line Extension viaduct. Originally slated for extension to , plans were revised in April 2021: the E branch was designated to serve Medford/Tufts while the D branch would extend to Union Square. This reallocation strategically aligns services around the Longwood Medical Area, with the E branch assigned to the longer Medford Branch owing to its shorter western segment.

The Union Square Branch officially opened as part of the E branch on March 21, 2022. From August 6 through August 20, E branch service between Heath Street and Copley was suspended for track replacement and installation of train protection systems; during this period, Union Square continued to be served by C and D branches. The stretch from Union Square to Government Center closed from August 22 to September 18 for final Medford Branch integration and removal of speed restrictions on the Lechmere Viaduct. Following reopening, both D and E trains provided service to Union Square. On November 1, Lechmere became the terminal for the E branch while test trains ran out-of-service beyond to Medford/Tufts; revenue operations on the Medford Branch commenced December 12, 2022.

In 2021, MBTA announced plans to upgrade platforms between Heath Street and Brigham Circle with accessible facilities replacing current non-accessible stops. The new platforms will accommodate two Type 10 vehicles simultaneously. Design work began in July 2023; construction will include new platforms at Riverway and Mission Park stations while Fenwood Road and Back of the Hill stops will be closed. As of December 2024, design completion is anticipated by late 2026 with construction scheduled for 2027 through 2029. The project budget is approximately $86 million.

Station listing

Location	Station	Opened	Notes and connections
Medford		December 12, 2022	:
			:
Somerville
			:
			:
East Cambridge		March 21, 2022	The Lechmere Viaduct began operation on June 1, 1912, initially served by surface connections until July 9, 1922. The surface-level station was in use from July 10, 1922, until May 23, 2020. :
West End		August 20, 1955
North End		June 28, 2004	Amtrak: : Fitchburg, Lowell, Haverhill, Newburyport/Rockport : : The original surface station operated between September 3, 1898 and March 27, 1997; the elevated station functioned from June 1, 1912 to June 24, 2004.
		September 3, 1898	: :
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